<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="refresh" content="3;url=login.html">
  <title>错误页面</title>
</head>
<body>
  <h2>你输入的用户名和密码错误，该页面将会在<span id="s">3</span>后跳转</h2>
</body>

<script>
  var s = document.getElementById("s");
  var i = 3;
  setInterval(function() {
    s.innerHTML = --i;
  }, 1000)
</script>
</html>